Preparation method and application of nanosheet adhesive capable of quickly adhering hydrogel

Abstract

The invention discloses a preparation method of a nanosheet adhesive capable of quickly adhering hydrogel, which is characterized by comprising the following steps: dissolving inorganic salt in a solvent, then ultrasonically dispersing uniformly, then adding a regulator and an organic ligand, and uniformly stirring at room temperature to obtain the nanosheet adhesive. The nanosheet adhesive of the present invention can reduce local dielectric constant and enhance electrostatic interaction to achieve rapid and continuous adhesion of hydrogel. In addition, due to the fact that holes exist in the surface of the nanosheet adhesive, the hydrogel network can penetrate through the nanosheet adhesive, and therefore the nanosheet adhesive can be tightly attached to the surface of the hydrogel. Meanwhile, the nanosheet adhesive prepared by the invention is easy to store, has long-term stability, is simple in preparation method, is water-resistant, has relatively strong adhesive force at low temperature and high temperature and in various solvents, and still keeps relatively high adhesive strength after being circulated for multiple times.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesive preparation, and particularly relates to a preparation method and application of a nanosheet adhesive for rapidly adhering hydrogels. Background Art

[0002] Wet adhesion plays an important role in biomedicine and biotechnology as well as more traditional coating and material technologies, and there is very little development of adhesives for adhering hydrogels. Traditional adhesives are usually polymers, but it is very difficult to bond hydrogels together using polymers, which requires chemical reactions, heating, pH changes, ultraviolet irradiation, or electric fields. In addition, hydrogels have a swelling property, and common adhesives often have difficulty maintaining good adhesion performance during the swelling process of hydrogels, resulting in the failure of the adhesion structure. Due to the large differences in chemical composition and physical properties among different types of hydrogels, it is difficult for general adhesives to achieve effective adhesion to most hydrogels. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and / or defects and provide at least the advantages described hereinafter.

[0004] To achieve these objects and other advantages of the present invention, there is provided a preparation method of a nanosheet adhesive for rapidly adhering hydrogels, including the following steps: dissolving an inorganic salt in a solvent, then ultrasonically dispersing it evenly, and subsequently adding a regulator and an organic ligand, and stirring evenly at room temperature to obtain the nanosheet adhesive.

[0005] Preferably, the inorganic salt is one or more of calcium nitrate tetrahydrate, calcium nitrite, aluminum nitrate nonahydrate, and magnesium nitrate hexahydrate.

[0006] Preferably, the regulator is N,N - diisopropylethylamine.

[0007] Preferably, the organic ligand is one or more of terephthalic acid, 2 - aminoterephthalic acid, and 2 - hydroxyterephthalic acid.

[0008] Preferably, the solvent is absolute ethanol.

[0009] Preferably, the molar ratio of the inorganic salt, the regulator, and the organic ligand is 1:1 - 10:0.5 - 2; the molar concentration of the inorganic salt in the solvent is 0.015 - 1.5 mol / L.

[0010] Preferably, the ultrasonic dispersion frequency is 20 - 40 kHz, ultrasonic dispersion is carried out for 30 - 45 min, and the stirring reaction is carried out for 2 - 8 h.

[0011] Preferably, when preparing the nanosheet adhesive, after adding inorganic salts to the solvent, a zein additive can also be added to the solvent. The specific method is as follows: First, dissolve the zein additive in 80% ethanol to obtain a zein additive solution, and then add it to the system. Among them, the dosage of the zein additive is 0.1-0.5 wt% of the solvent, and the mass ratio of the zein additive to ethanol is 2-3:80-100.

[0012] Preferably, the preparation method of the zein additive is as follows: Dissolve zein in an acetone solution, stir evenly, add lignin, continue to stir until it becomes viscous, and then heat to evaporate the solvent to obtain the zein additive. Among them, the mass ratio of zein, lignin to the acetone solution is 1:0.2-0.4:1.5-2, the concentration of the acetone solution is 70-80%, stir for 1-2 min, the heating temperature is 55-65 °C, and heat for 2-4 h.

[0013] The present invention also provides an application of the nanosheet adhesive. The nanosheet adhesive is used for quickly adhering hydrogels. When in use, first spray the nanosheet adhesive on the surface of a piece of hydrogel, and then another piece of hydrogel adheres thereto. Gently press, and the adhesion can be completed within 10 s.

[0014] The present invention has at least the following beneficial effects: The nanosheet adhesive of the present invention first removes the water on the surface of the hydrogel through the solvent and regulator in the adhesive, and then the nanosheets are stacked on the surface of the hydrogel, thereby reducing the local dielectric constant and strengthening the electrostatic interaction to achieve rapid adhesion. The nanosheets fix the solvent and regulator between the hydrogel and the nanosheets, so continuous adhesion can still be achieved with the swelling of the hydrogel. In addition, due to the pores on the surface of the nanosheet adhesive, the network of the hydrogel can penetrate the nanosheet adhesive, so that the nanosheet adhesive can tightly adhere to the surface of the hydrogel. At the same time, the nanosheet adhesive prepared by the present invention is a white gel-like liquid, which is easy to store and has long-term stability. The preparation method is simple, and it does not need to be prepared by heating, pressurizing, or irradiating with a specific wavelength light source. It can be prepared by stirring at room temperature, which is more energy-saving. The nanosheet adhesive for quickly adhering hydrogels of the present invention is water-resistant and has strong adhesion at low temperature, high temperature, and in various solvents, and still maintains a high adhesion strength after multiple cycles.

[0015] Other advantages, objectives, and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0016] Figure 1 It is the infrared spectrum diagram of the nanosheet adhesive prepared in Example 1 of the present invention;

[0017] Figure 2XRD pattern of the nanosheet adhesive prepared in Example 1 of the present invention;

[0018] Figure 3 SEM cross-sectional view of the nanosheet adhesive prepared in Example 1 of the present invention adhered to the surface of the hydrogel;

[0019] Figure 4 AFM image of the nanosheet adhesive prepared in Example 1 of the present invention;

[0020] Figure 5 Water vapor adsorption / desorption isotherm of the nanosheet adhesive prepared in Example 1 of the present invention;

[0021] Figure 6 Photograph of the hydrogel adhered with the nanosheet adhesive prepared in Example 1 of the present invention (left is treated with methyl orange staining);

[0022] Figure 7 Photograph of the nanosheet adhesive prepared in Example 1 of the present invention adhered to the hydrogel soaked in water. Detailed Description of the Invention

[0023] The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0024] It should be understood that the terms such as "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0025] Example 1

[0026] A preparation method of a nanosheet adhesive for rapidly adhering to a hydrogel, comprising the following steps:

[0027] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of terephthalic acid after uniform dispersion, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0028] An application of a nanosheet adhesive for rapidly adhering to a hydrogel: Spray the prepared nanosheet adhesive on a polyacrylamide hydrogel, and cover the adhesive with another hydrogel. Gently press twice to expel air, and the two hydrogels can be adhered in 10 s.

[0029] Figure 1 Infrared spectrum of the nanosheet adhesive prepared in this example; From Figure 1 It can be seen that

[0030] The infrared peak of the adhesive in Example 1 is at 511 cm -1, 626 cm -1 , 867 cm -1 are characteristic peaks of Ca - O, at 1386 cm -1 , 1558 cm -1 are characteristic peaks of terephthalic acid.

[0031] Figure 2 is the XRD pattern of the nanosheet adhesive prepared in this example; from Figure 2 it can be seen that there are diffraction peaks at 2θ = 13° and 25°, corresponding to the 101 and 202 crystal planes, indicating the successful synthesis of the nanosheet adhesive of the fast - adhering hydrogel in Example 1.

[0032] Figure 3 is the SEM cross - sectional view of the nanosheet adhesive prepared in this example adhered to the surface of the hydrogel. From Figure 3 it can be seen that the morphology of the nanosheet adhesive of the fast - adhering hydrogel is sheet - like and is more likely to accumulate on the surface of the hydrogel.

[0033] Figure 4 is the AFM image of the nanosheet adhesive prepared in this example. The thickness of the nanosheets is about 100 nm. Figure 5 is the water vapor adsorption - desorption curve of the nanosheet adhesive prepared in this example. From Figure 5 it can be seen that the nanosheet adhesive of the fast - adhering hydrogel can adsorb water vapor, and there is a part of water that is not desorbed during the desorption process.

[0034] Example 2

[0035] The difference between this example and Example 1 is that 0.015 mol of 2 - hydroxyterephthalic acid is used as the organic ligand, and the others are the same as in Example 1.

[0036] Example 3

[0037] The difference between this example and Example 1 is that 0.015 mol of 2 - aminoterephthalic acid is used as the organic ligand, and the others are the same as in Example 1.

[0038] Example 4

[0039] The difference between this example and Example 1 is that 0.015 mol of calcium nitrite is used as the inorganic salt, and the others are the same as in Example 1.

[0040] Example 5

[0041] The difference between this example and Example 1 is that 0.015 mol of aluminum nitrate nonahydrate is used as the inorganic salt, and the others are the same as in Example 1.

[0042] Example 6

[0043] This example is different from Example 1 in that 0.015 mol of magnesium nitrate hexahydrate is used as the inorganic salt, and the others are the same as in Example 1.

[0044] Example 7

[0045] A preparation method of a nanosheet adhesive for a fast-adhering hydrogel includes the following steps:

[0046] Dissolve 100 g of zein in 150 g of an acetone solution with a concentration of 80 wt%, add 20 g of lignin after stirring evenly, continue stirring for 20 min until it becomes viscous, and then heat at 58 °C for 2.5 h to evaporate the solvent to obtain a zein additive.

[0047] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, then dissolve 1.58 g of the zein additive in 100 mL of ethanol with a concentration of 80% to obtain a zein additive solution, add it to the calcium nitrate solution, then ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain a nanosheet adhesive.

[0048] An application of a nanosheet adhesive for a fast-adhering hydrogel: Spray the prepared nanosheet adhesive on a polyacrylamide hydrogel, and cover it with another hydrogel. Gently press twice to expel the air, and the two hydrogels can be adhered in 10 s.

[0049] Example 8

[0050] A preparation method of a nanosheet adhesive for a fast-adhering hydrogel includes the following steps:

[0051] Dissolve 100 g of zein in 150 g of an acetone solution with a concentration of 80 wt%, add 20 g of lignin after stirring evenly, continue stirring for 20 min until it becomes viscous, and then heat at 58 °C for 2.5 h to evaporate the solvent to obtain a zein additive.

[0052] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, then dissolve 2.36 g of the zein additive in 100 mL of ethanol with a concentration of 80% to obtain a zein additive solution, add it to the calcium nitrate solution, then ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain a nanosheet adhesive.

[0053] Example 9

[0054] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0055] Dissolve 100 g of zein in 150 g of an acetone solution with a concentration of 80 wt%, add 20 g of lignin after stirring evenly, continue to stir for 20 min until it becomes viscous, and then heat at 58 °C for 2.5 h to evaporate the solvent to obtain a zein additive;

[0056] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, then dissolve 3.16 g of the zein additive in 100 mL of ethanol with a concentration of 80% to obtain a zein additive solution, add it to the calcium nitrate solution, then ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid, and stir - react at room temperature for 8 h to obtain a nanosheet adhesive.

[0057] Comparative Example 1 (Comparative Examples 1 - 6 are different inorganic salts)

[0058] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0059] Dissolve 0.015 mol of calcium bromide x - hydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid after uniform dispersion, and stir - react at room temperature for 8 h to obtain a nanosheet adhesive.

[0060] Comparative Example 2

[0061] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0062] Dissolve 0.015 mol of calcium acetate monohydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid after uniform dispersion, and stir - react at room temperature for 8 h to obtain a nanosheet adhesive.

[0063] Comparative Example 3

[0064] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0065] Dissolve 0.015 mol of magnesium chloride hexahydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid after uniform dispersion, and stir - react at room temperature for 8 h to obtain a nanosheet adhesive.

[0066] Comparative Example 4

[0067] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0068] Dissolve 0.015 mol of magnesium bromide hexahydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0069] Comparative Example 5

[0070] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0071] Dissolve 0.015 mol of magnesium acetate tetrahydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0072] Comparative Example 6

[0073] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0074] Dissolve 0.015 mol of calcium chloride dihydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0075] Comparative Example 7 (Comparative Examples 7 - 8 are different organic ligands)

[0076] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0077] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, ultrasonically disperse it at 25 kHz for 30 min. After uniform dispersion, add 0.015 mol of N,N - diisopropylethylamine and 0.015 mol of 2 - fluoroterephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0078] Comparative Example 8

[0079] A preparation method of a nanosheet adhesive for a fast - adhering hydrogel, comprising the following steps:

[0080] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, ultrasonically disperse it for 30 min at 25 kHz. After uniform dispersion, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of tetrafluoroterephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0081] Comparative Example 9 (without adding lignin)

[0082] A preparation method of a nanosheet adhesive for a fast-adhering hydrogel, comprising the following steps:

[0083] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, then dissolve 1.58 g of zein in 100 mL of ethanol with a concentration of 80%, add it to the calcium nitrate solution, then ultrasonically disperse it for 30 min at 25 kHz. After uniform dispersion, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0084] Comparative Example 10 (without adding zein)

[0085] A preparation method of a nanosheet adhesive for a fast-adhering hydrogel, comprising the following steps:

[0086] Dissolve 0.015 mol of calcium nitrate tetrahydrate in 1 L of absolute ethanol, then dissolve 1.58 g of lignin in 100 mL of ethanol with a concentration of 80%, add it to the calcium nitrate solution, then ultrasonically disperse it for 30 min at 25 kHz. After uniform dispersion, add 0.015 mol of N,N-diisopropylethylamine and 0.015 mol of terephthalic acid, and stir and react at room temperature for 8 h to obtain the nanosheet adhesive.

[0087] Use the nanosheet adhesives prepared in Examples 1-9 and Comparative Examples 1-8 to bond polyacrylamide hydrogels respectively. The method is as follows: Spray the prepared nanosheet adhesive on the polyacrylamide hydrogel, cover another polyacrylamide hydrogel on the adhesive, gently press twice to expel air, and the two hydrogels can be adhered in 10 s. Test the adhesion strength of the finally adhered hydrogel, and the test results are shown in Table 1 below.

[0088] Table 1 Adhesion strength of examples and comparative examples

[0089] Example 1 2 3 4 5 6 7 8 9 Adhesion strength (Pa) 3863 3121 3727 3719 3072 3541 4102 4227 4396 Comparative example 1 2 3 4 5 6 7 8 9 10 Adhesion strength (Pa) 2492 2936 2122 2753 1716 2885 2538 2417 3995 3861

[0090] As can be seen from Table 1, compared with the inorganic salts used in Comparative Examples 1-6, different inorganic salt anions were selected in Examples 1-6 of the present invention. The adhesives prepared from nitrates in Examples 1-6 had higher adhesion strength. This is because the lattice energy of nitrates is relatively small and nitrate ions are prone to form hydrogen bonds, so the adhesives prepared in the examples of the present invention had higher adhesion strength. Compared with the organic ligands used in Comparative Examples 7-8, the fluorine-containing ligands in Comparative Examples 7-8 had a hydrophobic effect and were unevenly dispersed in the solvent, resulting in low adhesion strength of the prepared adhesives. However, the organic ligands used in Examples 1-6 were not hydrophobic, so the adhesives prepared in the examples of the present invention had higher adhesion strength. In addition, on the basis of Example 1, in Examples 7-9, zein additives were introduced into the adhesive system. The film-forming property of zein and the multi-functional group structure of lignin could form a dense adhesion layer at the interface, enhancing the interaction with the substrate and contributing to further improving the adhesion strength of the adhesive. At the same time, as can be seen from Table 4, the adhesion strength of the nanosheet adhesive underwater was also improved. This is because the combined hydrophobicity of zein and lignin could effectively repel water, reducing the interference of water molecules in the underwater environment on the adhesion interface, and the molecular structure of lignin could remain stable underwater and was not easily hydrolyzed, thus improving the underwater adhesion performance.

[0091] Application Example 1

[0092] The nanosheet adhesives prepared in Example 1 were used to bond polyethylene glycol hydrogel, sodium alginate hydrogel, polyacrylic acid hydrogel, and polyvinyl alcohol hydrogel respectively, and the adhesion strength was tested. The results are shown in Table 2 below.

[0093] Table 2 Adhesion strength when bonding different hydrogels

[0094] Polyethylene glycol hydrogel Sodium alginate hydrogel Polyacrylic acid hydrogel Polyvinyl alcohol hydrogel Adhesion strength (Pa) 3632 3150 3562 3655

[0095] The nanosheet adhesive of Example 1 was used to bond polyacrylamide hydrogel for cyclic adhesion hydrogel testing, and the adhesion strength is shown in Table 3.

[0096] Table 3 Adhesion strength of the nanosheet adhesive of Example 1 for cyclic adhesion of hydrogels

[0097] Number of cycles 1 2 3 4 5 6 7 8 9 10 Adhesion strength (Pa) 3863 3236 3236 3203 3138 3039 2776 2348 2052 1953

[0098] The nanosheet adhesives of Example 1, Example 7, and Comparative Examples 9-10 were bonded to polyacrylamide hydrogel and then immersed in water for different times, and the adhesion strength was tested. The adhesion strength is shown in Table 4.

[0099] Table 4 Adhesion strength of the nanosheet adhesives of Example 1 and Examples 7-9 after bonding hydrogels and immersed in water for different times

[0100] 0.0028h 2h 24h 192h 480h Adhesion strength of Example 1 (Pa) 4400 4300 4217 3576 3272 Adhesion strength of Example 7 (Pa) 4652 4541 4414 3639 3399 Adhesion strength of Comparative Example 9 (Pa) 4472 4325 4276 3570 3314 Adhesion strength of Comparative Example 10 (Pa) 4518 4371 4301 3608 3385

[0101] (It should be noted that the adhesion strength of the nanosheet adhesive in water is further improved compared to that in air.)

[0102] The nanosheet adhesive of Example 1 was used to bond the polyacrylamide hydrogel and then immersed in different solvents, and the adhesion strength was tested. The adhesion strength is shown in Table 5.

[0103] Table 5 Adhesion strength of the nanosheet adhesive of Example 1 to the hydrogel in different solvents

[0104] Solvent Water Brine Aqueous formaldehyde solution Hydrogen peroxide solution Aqueous potassium permanganate solution Adhesion strength (Pa) 4400 2634 2349 1148 1632

[0105] The nanosheet adhesive of Example 1 was used to bond the polyacrylamide hydrogel and then immersed in water at different temperatures, and the adhesion strength was tested. The adhesion strength is shown in Table 6.

[0106] Table 6 Adhesion strength of the nanosheet adhesive of Example 1 to the hydrogel in water at different temperatures

[0107] Temperature (°C) 0 10 20 40 60 Adhesion strength (Pa) 3995 4348 4400 3952 3065

[0108] The adhesion strength of the nanosheet adhesive of Example 1 to the polyacrylamide hydrogels with different swelling ratios is shown in Table 7.

[0109] Table 7 Adhesion strength of the nanosheet adhesive of Example 1 to hydrogels with different swelling ratios

[0110] Swelling ratio 10％ 20％ 30％ 40％ 50％ Adhesion strength (Pa) 2945 2709 2435 2164 1935

[0111] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A method for preparing a nanosheet adhesive for rapid hydrogel adhesion, characterized in that: The following steps are involved: The inorganic salt is dissolved in a solvent and then dispersed uniformly by ultrasonication, and then a regulator and an organic ligand are added and stirred uniformly at room temperature to obtain a nanosheet adhesive.

2. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The inorganic salt is one or more of calcium nitrate tetrahydrate, calcium nitrite, aluminum nitrate nonahydrate, and magnesium nitrate hexahydrate.

3. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The regulator is N,N-diisopropylethylamine.

4. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The organic ligand is one or more of terephthalic acid, 2-aminoterephthalic acid, and 2-hydroxyterephthalic acid.

5. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The solvent is anhydrous ethanol.

6. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The molar ratio of the inorganic salt, the regulator and the organic ligand is 1:1-10:0.5-2; the molar concentration of the inorganic salt in the solvent is 0.015-1.5 mol / L.

7. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: The ultrasonic dispersion frequency is 20 to 40 kHz, the ultrasonic dispersion is carried out for 30 to 45 minutes, and the stirring reaction is carried out for 2 to 8 hours.

8. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 1, characterized in that: When preparing the nanosheet adhesive, after adding inorganic salts to the solvent, an alcohol-soluble protein additive can also be added to the solvent. The specific method is: first dissolving the alcohol-soluble protein additive in 80% ethanol to obtain an alcohol-soluble protein additive solution, and then adding the alcohol-soluble protein additive solution to the system; wherein the amount of the alcohol-soluble protein additive is 0.1-0.5wt% of the solvent, and the mass ratio of the alcohol-soluble protein additive to ethanol is 2-3:80-100.

9. The method for preparing the nanosheet adhesive for rapid hydrogel adhesion according to claim 8, characterized in that: The preparation method of the alcohol-soluble protein additive comprises the following steps: dissolving zein in an acetone solution, adding lignin after stirring evenly, continuing stirring until viscous, and then heating and evaporating the solvent to obtain the alcohol-soluble protein additive; wherein the mass ratio of zein, lignin and acetone solution is 1:0.2-0.4:1.5-2, the concentration of acetone solution is 70-80%, stirring for 1-2 minutes, heating at a temperature of 55-65° C., and heating for 2-4 hours.

10. An application of a nanosheet adhesive prepared by the preparation method according to any one of claims 1 to 9, characterized in that: It is used to quickly adhere hydrogels. When using it, first spray the nanosheet adhesive on the surface of a piece of hydrogel, then attach another piece of hydrogel on it, press gently, and the adhesion can be completed within 10 seconds.

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